实验三

任务1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#define N 80
   
void print_text(int line, int col, char text[]);  
void print_spaces(int n);  
void print_blank_lines(int n);  
   
int main() {
    int line, col, i;
    char text[N] = "hi, April~";
   
    srand(time(0));  
   
    for(i = 1; i <= 10; ++i) {
        line = rand() % 25;
        col = rand() % 80;
        print_text(line, col, text);
        Sleep(1000);  
   }
   return 0;
}
 
void print_spaces(int n) {
    int i;
    
    for(i = 1; i <= n; ++i)
        printf(" ");
}
 
void print_blank_lines(int n) {
    int i;

    for(i = 1; i <= n; ++i)
        printf("\n");
}
 
void print_text(int line, int col, char text[]) {
    print_blank_lines(line-1); 
    print_spaces(col-1);  
    
    printf("%s", text);  
}

 这个程序实现的功能是连续每隔1s随机打印10次行在[0,25)列在[0,80)之间的一串hi，April~字符

任务二

#include <stdio.h>
long long fac(int n);  

int main() {
    int i, n;
    
    printf("Enter n: ");
    scanf("%d", &n);
    
    for (i = 1; i <= n; ++i)
printf("%d! = %lld\n", i, fac(i));
return 0;
} 

long long fac(int n) {
    static long long p = 1;
    printf("p = %lld\n", p);
    p = p * n;

    return p;
}

运行结果截图

 #include <stdio.h>
int func(int, int);  

int main() {
    int k = 4, m = 1, p1, p2;
    
    p1 = func(k, m);  
    p2 = func(k, m);  
    printf("%d, %d\n", p1, p2);
    
    return 0;
}
 
int func(int a, int b) {
    static int m = 0, i = 2;
    
    i += m + 1;
    m = i + a + b;
    
    return m;
}

运行结果截图

实验运行结果与我理论分析得到的结果一致。

static 局部变量的特性是它在函数调用结束后，它的值仍然存在，并可能影响到下一次调用的过程。

任务三

#include <stdio.h>
long long func(int n);  

int main() {
    int n;
    long long f;
    
    while (scanf("%d", &n) != EOF) {
        f = func(n);  
        printf("n = %d, f = %lld\n", n, f);
    }

    return 0;
}

long long func(int n){
    long long s;
 
    if(n==1)
      s=1;
      else
        s=2*func(n-1)+1;
       
    return s;
       
    }

运行结果截图

任务四

#include <stdio.h>
int func(int n,int m);

int main(){
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF){
        printf("n=%d,m=%d,ans=%d\n",n,m,func(n,m));
        
    }    
    return 0;
}

int func(int n,int m){
if (n==m || m==0){

return 1;}
else if(n<m){return 0;
}

return func(n-1,m)+func(n-1,m-1);

}

运行结果截图

 任务五

#include <stdio.h>
double mypow(int x, int y); 
int main() 
{
    int x, y;
    double ans;
    while(scanf("%d%d", &x, &y) != EOF)
     {
        ans = mypow(x, y); 
        printf("%d的%d次方: %g\n\n", x, y, ans);
    }
    return 0;
}

double mypow(int x, int y)
{
    int i;
    double ans=1.0;
    if(y>=0)
    {
        for(i=1;i<=y;i++)
            ans=ans*x;
        return ans;
    }
    else
    {
        for(i=1;(i+y)<=0;i++)
            ans=ans/x;
        return ans;
    }
}

运行结果截图

#include <stdio.h>
double mypow(int x, int y); 
int main() 
{
    int x, y;
    double ans;
    while(scanf("%d%d", &x, &y) != EOF)
     {
        ans = mypow(x, y); 
        printf("%d的%d次方: %g\n\n", x, y, ans);
    }
    return 0;
}

double mypow(int x, int y)
{
    double ans=1;
    if(y==0)
    ans=1;
    if(y>0)
        ans=ans*x*mypow(x,y-1);
    if(y<0)
        ans=ans/x*mypow(x,y+1);
    return ans;
}

运行结果截图

任务六

#include<stdio.h>
#include<math.h>
void hanoi(int n,char from,char temp,char to);
void move(int n,char from,char to);
int main()
{
    int n;
    while(scanf("%d", &n) != EOF)
    {
        hanoi(n,'A','B','C');
        printf("total degree:%g\n",pow(2,n)-1);
    }
    return 0;
}

void hanoi(int n,char from,char temp,char to)
{
    if(n==1)
        move(n,from,to);
    else
    {
        hanoi(n-1,from,to,temp);
        move(n,from,to);
        hanoi(n-1,temp,from,to);
    }
}
void move(int n,char from,char to)
{
    printf("%d:%c-->%c\n",n,from,to);
}

运行结果截图

任务七

#include<stdio.h>
int is_prime(int n);
int main()
{
    int n,i;
    for(n=4;n<=20;n+=2)
    {
        for(i=2;i<=(n/2);i++)
        {
            if(is_prime(i)&&is_prime(n-i))
            {
                printf("%d = %d + %d\n",n,i,n-i);
                break;
            }
        }
    }
    return 0;
 } 
 int is_prime(int n)
 {
     int i,flag=1;
     for(i=2;i<n;i++)
     {
         if(n%i==0)
             flag=0;
     }
     return flag;
 }

运行结果截图

任务八

#include <stdio.h>
#include <math.h>
long func(long s);
int main() 
{
    long s, t;
    printf("Enter a number: ");
    while (scanf("%ld", &s) != EOF) 
    {
        t = func(s); 
        printf("new number is: %ld\n\n", t);
        printf("Enter a number: ");
    }
    return 0;
}

long func(long s)
{
    long ans=0;
    long x,i=1;
    while(s!=0)
    {
        x=s%10,s=s/10;
        if(x%2!=0)
        {
            ans=ans+x*i;
            i=i*10;
        }    
    }
    return ans;
}

运行结果截图